1. Field of the Invention
The present invention relates to a power-generating roof tile used as a roof member for a building and equipped with a photovoltaic module capable of solar-light power generation.
2. Description of the Related Art
A photovoltaic module capable of converting solar-light energy into electric energy is known. The use of a photovoltaic module by mounting it on a roof member of a building is also known from, for example, Jpn. UM Appln. KOKAI Publication No. 1-148417 and Jpn. Pat. Appln. KOKAI Publication No. 10-72910. Cables led from power-generating roof tiles equipped with a photovoltaic module are connected to each other, thereby electrically connecting a large number of photovoltaic modules in series or in parallel.
Jpn. UM Appln. KOKAI Publication No. 1-148417 describes a configuration in which a photovoltaic module is provided on the lower surface of a flat roof tile, and the cable of the photovoltaic module is led through a space made in reverse surfaces of the both ends of the upper edge of the flat tile. Although this publication describes the leading of the cable of a photovoltaic module from the reverse surface of a roof tile main body, no reference is made to a construction involving leading a cable to the ridge side of a roof.
Jpn. Pat. Appln. KOKAI Publication No. 10-72910 describes a configuration in which a photovoltaic module is provided on the top surface of a flat roof tile, and a terminal box is provided on the reverse surface of the flat roof tile, thereby leading a wiring member (cable) from the terminal box. Although this publication describes the leading of a cable from a terminal box to the reverse surface of a roof tile main body, no reference is made to a construction involving leading a cable to the ridge side of a roof.
Another roof tile equipped with a photovoltaic module, as stated below, is proposed. A photovoltaic module is provided on the top surface of a roof tile main body, and a terminal-box-receiving recess is provided in the roof tile main body, projecting from the reverse surface thereof. A terminal box attached to the reverse surface of the photovoltaic module is contained in the terminal-box-receiving recess. An output lead-out cable connected to the terminal box is led through a cable-leading hole formed in the bottom wall of the terminal-box-receiving recess.
The power-generating roof tile is rainproofed as follows. The photovoltaic module is adhered to the roof tile main body by an adhesive. The photovoltaic module is adhered, by an adhesive, to the bottom of the recess provided in the roof tile main body. Further, the clearance between the photovoltaic module and the inner peripheral surface of the recess is filled with a caulking member.
However, adhesives or caulking members can be easily degraded. In particular, if they are mounted on, for example, a roof where they are exposed to the solar-light, they can quickly degrade due to excessive heat, or from water-related corrosion. If the adhesive or caulking member cracks, rainwater may enter between the roof tile main body and the photovoltaic module.
It is possible that rainwater entering through the reverse side of the photovoltaic module will flow into the terminal-box-receiving recess. Power-generating roof tiles are usually arranged on the inclined sarking of a roof. Since the roof is thus inclined, rainwater entering and collecting in the bottom of the terminal-box-receiving recess leaks out over the upper surface of the recess. The rainwater may also run out through a cable-guiding hole formed at the bottom of the terminal-box-receiving recess. Accordingly, in particular, if the slope of the roof is not steep, it is very possible that the connection between a terminal box and the cable in the terminal-box-receiving recess will be exposed to rainwater entering it, leading to corrosion or a short-circuit thereof.
In addition, the sarking is provided very close to the terminal-box-receiving recess. In a configuration in which a cable is guided through the bottom wall of the terminal-box-receiving recess, the cable led in the direction of the sarking is arranged along the sarking. Therefore, the cable is sharply bent at substantially right angles to the direction in which the cable is led from a cable lead-out hole. Since the cable is thus bent, it is strongly pressed against the edge of the lead-out hole. Therefore, it is very possible that the insulating coating of the cable will be damaged. In particular, where the roof tile main body is formed of cement, the edge of a cable lead-out hole is burred, and hence its insulating coating is more easily damaged.
It is an object of the present invention to provide a power-generating roof tile capable of preventing, for example, electrical short-circuiting due to the entrance of rainwater, and reducing the possibility of the output lead-out cables being damaged.
A power-generating roof tile according to the invention includes a photovoltaic module having a reverse surface thereof provided with a terminal box, and a tile main body including a recess that receives the photovoltaic module, and a terminal-box recess that is provided at a bottom of the recess and receives the terminal box. The tile main body further includes a cable lead-out section located at a ridge-side portion thereof where the tile main body is mounted on an inclined roof. Positive-side and negative-side output lead-out cables connected to the terminal box, which are single-core cables independent of each other, are led from the cable lead-out section to the ridge side.
In the invention, the tile main body is made of an inorganic material such as clay, a synthetic resin material or cement, a metal material, or a composite material thereof Electric wires coated with an insulator are used as the output lead-out cables. The photovoltaic module is formed by, for example, sequentially forming, on a substrate made of a transparent insulating material such as transparent glass or a transparent synthetic resin, a transparent electrode layer, a semiconductor layer capable of photoelectric conversion, and a reverse-side electrode layer in this order, using a thin-film manufacture technique, and then coating the reverse surface with a sealing material layer. The sealing material layer is used to insulate, waterproof or mechanically protect a to-be-sealed layer. An amorphous semiconductor layer is suitable for the semiconductor layer. However, the semiconductor layer is not limited to this but may be a monocrystal, polycrystal or microcrystal semiconductor layer. Alternatively, a silicon-based material or a compound material may be used. Further, a tandem-type photovoltaic module may be used.
In the invention, the two single-core output lead-out cables are independent of each other so as not to be used as a double-core cable. These single-core output lead-out cables are led to the ridge side from the cable lead-out section provided at a ridge-side portion of the tile main body. By virtue of this structure, even if, for example, rainwater enters the terminal-box-receiving recess that receives the terminal box, there is only a slim possibility of the rainwater reaching a connection of the terminal box and the cables. Accordingly, corrosion or electrical short-circuiting at the connection can be avoided. Moreover, since the two cables are led to the ridge side, it is not necessary to sharply bend the lead cables along the sarking about the cable lead-out section. This prevents the output lead-out cables from being damaged by the edge of the cable lead-out section. As a result, the invention can provide a high quality power-generating roof tile.
The invention includes the feature that the cable lead-out section crosses a ridge-side edge portion of the tile main body and communicates with the terminal-box-receiving recess. In this case, it is preferable that the cable lead-out section is formed of an opening groove in an upper surface of the ridge-side edge portion of the tile main body.
In the invention, the cable lead-out section and hence the connection of the terminal box and the cables can be located at a high level. Accordingly, the number of occasions in which the connection is exposed to the rainwater that has entered the terminal-box-receiving recess can be minimized. If the cable lead-out section is formed of a groove, the cables can be easily inserted through the cable lead-out section.
Furthermore, a power-generating roof tile according to the invention includes a photovoltaic module having a reverse surface thereof provided with a terminal box, and a tile main body including a recess that receives the photovoltaic module, and a terminal-box recess that is provided at a bottom of the recess and receives the terminal box. The tile main body further includes a cable lead-out section located at a ridge-side side wall of the terminal-box-receiving recess where the tile main body is mounted on an inclined roof. Output lead-out cables connected to the terminal box are led from the cable lead-out section to the ridge side.
In the invention, positive-side and negative-side output lead-out cables, which are independent of each other so as not to be used as a double-core cable, can be used as the output lead-out cables. Alternatively, a single double-core cable can be used, which is formed by combining positive-side and negative-side output lead-out cables as single-core cables.
In the invention, the output lead-out cables connected to the terminal box are led to the ridge side from a ridge-side side wall of the terminal-box-receiving recess of the tile main body. By virtue of this structure, even if, for example, rainwater enters the terminal-box-receiving recess that receives the terminal box, the number of occasions is small, in which the rainwater reaches a connection of the terminal box and the cables. Accordingly, corrosion or electrical short-circuiting at the connection can be avoided. Moreover, since the cables are led to the ridge side, it is not necessary to sharply bend the lead cables along the sarking about the cable lead-out section. This prevents the output lead-out cables from being damaged by the edge of the cable lead-out section. As a result, the invention can provide a high quality power-generating roof tile.
The invention includes the feature that the cable lead-out section is a hole extending through the side wall. The cable lead-out section of the invention does not reduce the strength of the ridge-side edge of the tile main body.
The invention also includes the feature that the output lead-out cables are led from the ridge-side side surface of the terminal box. Accordingly, the output lead-out cables can be led to the ridge side without bypassing them around the terminal box.
The invention further includes the feature that the terminal-box-receiving recess is provided at a width-directional central portion of the tile main body, and the cable lead-out section communicates with a width-directional central portion of a ridge-side side wall of the receiving recess. Accordingly, the positive-side and negative-side output lead-out cables can be made to the same length.
The invention includes the feature that a drain section is provided in an eaves-side portion of the tile main body so that it communicates with the recess and crosses the eaves-side edge portion. The drain section is formed of, for example, an opening groove in the upper surface of the eaves-side edge of the tile main body, or a hole extending through the eaves-side edge.
It is sufficient if one or more drain sections are provided. The drain section can have any size. The drain section may be provided obliquely.
In the invention, even if rainwater enters the recess in the tile main body that is mounted on an inclined roof, it can be discharged to the outside of the recess through the drain sections formed in the eaves-side edge of the tile main body. This drainage structure enables the amount of rainwater entering the terminal-box-receiving recess to be reduced, thereby keeping the water level in the receiving recess low. Thus, the structure is effective in preventing corrosion or electrical short-circuiting at the connection of the terminal box and the cables.
In addition, a power-generating roof tile according to the invention includes a photovoltaic module having a reverse surface thereof provided with a terminal box, and a tile main body including a recess that receives the photovoltaic module, and a terminal-box recess that is provided at a bottom of the recess and receives the terminal box. The tile main body further includes a thin wall section located in a ridge-side side wall of the terminal-box-receiving recess where the tile main body is mounted on an inclined roof. The thin wall section can be removed forming a cable lead-out section. Output lead-out cables connected to the terminal box are led from the cable lead-out section to the ridge side.
Furthermore, a power-generating roof tile according to the invention includes a photovoltaic module and a tile main body. The photovoltaic module has a reverse surface thereof provided with a terminal box, the box is connected to positive-side and negative-side output lead-out cables. The tile main body is mounted on an inclined roof, and includes a recess that receives the photovoltaic module, a terminal-box-receiving recess that is provided at a bottom of the recess and receives the terminal box, and a cable lead-out section arranged in a side wall on a roof ridge side of the terminal-box-receiving recess in such a manner as to be directed toward the ridge, for leading the two output lead-out cables toward the ridge.